# How do you find the derivative of -sin^2(x)?

$- 2 \sin \left(x\right) \cos \left(x\right)$
$\frac{d}{\mathrm{dx}} \left[- {\sin}^{2} \left(x\right)\right] = - 2 \sin \left(x\right) \frac{d}{\mathrm{dx}} \left[\sin \left(x\right)\right] = - 2 \sin \left(x\right) \cos \left(x\right)$